This is a bit of an odd question but I was just wondering while out riding today. How much can you lean you bike as you go into a corner?How much do you lean your bike? What are the limits, obviously the biggest one is sliding sides ways on your knee. This is sort of an abstract question because you'd have to take into account factors like speed and the angle which you're turning. I've slid out on my fixie in the rain, I definitely know that limit, but on a dry day on your roadie when you can poke a knee out, how far do you lean over?

Too many varying factors. The limit will essentially be controlled by the friction available between your tyre and the road surface. So that brings your tyre choice and the road surface into play. Then there's your weight that is the next major factor and so on.......

Also depends on whether you intend to keep pedaling through the corner. If you do, the bottom-bracket drop and crank length measurements become important, as you don't want to scrape your pedals on the ground. When I'm cornering, I'll typically lean the bike but keep my body relatively upright: I find that to be more stable (or at least, it works for me).

This discussion of cornering technique is all getting a bit remote from the OP's question about safe lean angles. However technique does play a significant role in how well you can corner and how fast. One point related to this is the benefits of two things:

1. Putting your inside knee out - always makes me feel much more reassurred about the corner but I don't know why - is it just the weight of my leg further to the inside?2. Putting all your weight on the outside pedal - this is particularly effective in controlling a fully loaded touring bike or MTB on a rough gravel road descent. I have seen people discover this technique after a little instruction and be amazed at how much it helps them corner really well. Again, I don't know why it works.

Maybe someone with a physics background can analyze these techniques.

Riding bikes in traffic - what seems dangerous is usually safe; what seems safe is often more dangerous.

As I understand it, tilting the bike can move the centre of mass from under the bottom bracket to the inside of the corner, so putting your weight through the rigid outside leg with the pedal at 6 o'clock helps move it back.

My girlfriend had the terrible habit of putting the inside leg down when going around corners. She got away with it because she rides fairly slowly.

For what it is worth, I put my outside leg down with my weight on that pedal and lean into the corner (body and bike). Breaking before the corner is also important. I am no speed demon and I certainly ride within my limits (there's no way in hell I want to come off a bike at 60-80 km/hr!). Actually once I did come off at around 50-60 km/hr but that was on grass fortunately (damn dew).

Leaning in TurnsTo turn a bicycle, you must lean inward toward the direction of the turn. The faster you are going, and the sharper the turn, the more you must lean. You have no choice about this, for a given speed and turn radius, the center of gravity of the bike/rider must be moved sideways a particular amount or the bicycle will not balance. What you do have control over is whether you lean the bicycle more than, less than, or the same amount that you lean your body, to get the overall center of gravity to the place that it has to go.

•Leaning the bicycle sharply while keeping your upper body more upright This approach is popular with beginners who are scared to lean over sideways, and who feel less disoriented by keeping their bodies more upright. -- though actually, they don't. The cyclist is much heavier than the bicycle, which leans over farther, instead.

Captaining a tandem with a stoker who doesn't know about leaning in turns can be a very unsettling experience, because you must lean farther to compensate.

Keeping the upper body more upright is recommended by some racers and coaches as offering the possibility of recovering from a skid, but I don't believe it.

[I think there might be something to this. If you start to skid out, you might be able to yank the bicycle up and momentarily press the wheels harder into the road surface to gain more traction -- though the side force also might potato-chip a wheel, or roll a tubular off the rim.

Racers also sometimes drop the knee that is to the inside of the turn. Yanking the knee inward may also help ro recover from a skid.

Also see Jobst Brandt's comments, below -- John Allen.]

•Leaning the upper body sharply while keeping the bicycle more upright This approach is popular with riders who are afraid of striking a pedal on the road. This is a particular concern for riders of fixed-gear bicycles, since they cannot coast through corners.

This technique is also recommended by some racers and coaches as offering the possibility of recovering from a skid, but I don't believe it.

[Neither do I -- but, as Sheldon says, this may be necessary to avoid a pedal strike with a fixed-gear bicycle -- John Allen.] •Leaning the upper body and the bicycle together, keeping them in line as when riding straight. This technique has the advantage of keeping the steering axis, tire contact patches and center of gravity all in the same plane. This preserves the proper handling characteristics of the bicycle, and makes a skid less likely. You can verify this yourself by performing an experiment suggested by Jobst Brandt:

"Some riders believe that sticking out their knee or leaning their body away from the bike, improves cornering. Sticking out a knee is the same thing that riders without cleats do when they stick out a foot in dirt track motorcycle fashion. It is a useless but reassuring gesture that, on uneven roads, actually works against you. Any body weight that is not centered over the bicycle (leaning the bike or sticking out a knee) puts a side load on the bicycle, and side loads cause steering motions if the road is not smooth. Getting weight off the saddle is also made more difficult by such maneuvers. "To verify this, ride down a straight but rough road standing on one pedal with the bike slanted, and note how the bike follows an erratic line. In contrast, if you ride centered on the bike you can ride no-hands perfectly straight over rough road. When you lean off the bike you cannot ride a smooth line over road irregularities, especially in curves. For best control, stay centered over your bike."

For the amount of lean I don't think it matters too much, as long as you're getting through the corner

My half-assed theory (there are lots of internet forum discussions about it, see motorcycle forums also and swap "pedal" for "peg") below...

Imagine your bike didn't lean at all. Basically it stayed flat, just like a car or trike when cornering.

To turn a corner, you turn the bars. When you turn the bars/steering, the front wheel turns to exactly the same angle as the bars.

Now start to lean the bike to the inside of the corner. Now when you turn the bars, the effect is amplified at the contact point of the tyre - you only need a tiny steering angle 9at the bars) to produce a large change in the angle of the contact patch at the tyre.

If you can't visualise that, take it to the extreme - imagine a bike laid flat on its side: the tiniest steering angle makes the very front of the tyre the bit that touches the ground (the contact patch), and it will want to roll 90° to the direction of the rear wheel).

So the more you lean the bike, the more sensitive the steering becomes. The less you lean it, the less sensitive it is to steering inputs. "Twitchy" could replace the word "sensitive" - if you're not a pro/not concentrating, it could be difficult to respond with the necessary accuracy at the bars.

Back to the pedal weighting: weighting the outside pedal is in effect the same as leaning off to the inside of the bike. It will try to stand the bike more upright. Standing the bike more upright will make the steering less twitchy, ergo, more easy to control.

I'm not sure if the above is accurate though, it's just my guesswork.

Another factor is that weighting the outside pedal pushes the saddle into the inside of your outer thigh (or if you are out of the saddle, loads up your hands on the steering). This effectively locks your body to the frame more rigidly, making it easier to feel what it is doing and therefore making corrective responses more intuitive.

FYI Lord Sheldon advocates against leaning off the bike on the basis of the asymmetric torque that is applied through the steering if you have to brake mid-corner.

Are they trying to say you turn your wheel in the opposite direction to cornering? I've paid careful attention to my turning style over the last few days and I steer (ever so slightly) the way I want to go when leaning the bike over to turn. Not the opposite direction.

Countersteer

Countersteer is a popular subject for people who belatedly discover or rediscover how to balance. What is not apparent, is that two wheeled vehicles can be controlled ONLY by countersteer, there is no other way. Unlike a car, a bicycle cannot be diverted from a straight path by steering the wheel to one side. The bicycle must first be leaned in that direction by steering it ever so slightly the other way. This is the means by which a broomstick is balanced on the palm of the hand or a bicycle on the road. The point of support is moved beneath the mass, in line with the combined forces of gravity and cornering, and it requires steering, counter and otherwise. It is so obvious that runners never mention it, although football, basketball, and ice hockey players conspicuously do it.

Countersteering is turning the bars very briefly to one direction (say right) in order to initiate a turn in the opposite direction (left). It moves the front wheel out to the right, initiating the lean angle needed to turn left.

MattyK wrote:Another factor is that weighting the outside pedal pushes the saddle into the inside of your outer thigh (or if you are out of the saddle, loads up your hands on the steering). This effectively locks your body to the frame more rigidly, making it easier to feel what it is doing and therefore making corrective responses more intuitive.

I think this is probably the major benefit of weighting the outside pedal. Stability and predictable control. Any lack of control is going to be particularly noticeable on a rough gravel road with a heavily loaded bike, hence we get real cornering improvements from doing this.

Riding bikes in traffic - what seems dangerous is usually safe; what seems safe is often more dangerous.